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β-环糊精不仅有增溶作用,还具有由羟基与反应底物的相互作用所产生的催化作用,以及由此产生的β-环糊精与反应底物的相互作用对于反应选择性的影响.在β-环糊精存在下,以H2O2/H3BO3/H2SO4组成的反应体系,以水为唯一溶剂,对甲氧基苯甲醛通过Baeyer-Villiger氧化得到对甲氧基苯酚.β-环糊精可与对甲氧基苯甲醛和对甲氧基苯酚形成包结物,使反应速率降低,有效地保护甲氧基,防止其继续反应,提高反应的选择性.采用1HNMR,UV-Vis,FT-IR对β-环糊精与对甲氧基苯甲醛的相互作用进行表征分析,发现在水相中β-环糊精与对甲氧基苯甲醛可以自发地形成物质的量比为1∶1的包结物,其吉布斯函变△γGm(298K)为-14.577kJ·mol-1,稳定常数Ka为358,结合FT-IR分析推测出包结物中醛基较多地位于β-环糊精空腔的小口端.
β-Cyclodextrin has not only a solubilizing action but also a catalytic action due to the interaction of the hydroxyl group with the reaction substrate and the interaction between the β-cyclodextrin and the reaction substrate thus produced, which are selective for the reaction Influence in the presence of β-cyclodextrin, the reaction system consisting of H2O2 / H3BO3 / H2SO4, water as the sole solvent, p-methoxybenzaldehyde by Baeyer-Villiger oxidation of p-methoxyphenol β-cyclodextrin Escherichia coli and p-methoxybenzaldehyde and p-methoxyphenol formed inclusion complex, which reduced the reaction rate and effectively protected the methoxy group to prevent it from continuing reaction and enhanced the selectivity of the reaction.Using 1HNMR, UV-Vis, FT-IR analysis of the interaction between β-cyclodextrin and p-methoxybenzaldehyde showed that the amount of β-cyclodextrin and p-methoxybenzaldehyde spontaneously formed in the aqueous phase was 1 : 1, the Gibbs box △ GmG (298K) -14.577kJ · mol-1, the stability constant Ka is 358, combined with FT-IR analysis of the inclusion of aldehyde more Located in the small mouth of β-cyclodextrin cavity.